com.nineoldandroids.animation
Class Keyframe

java.lang.Object
  com.nineoldandroids.animation.Keyframe

All Implemented Interfaces:

Cloneable

public abstract class Keyframe
extends Object
implements Cloneable

This class holds a time/value pair for an animation. The Keyframe class is used by ValueAnimator to define the values that the animation target will have over the course of the animation. As the time proceeds from one keyframe to the other, the value of the target object will animate between the value at the previous keyframe and the value at the next keyframe. Each keyframe also holds an optional TimeInterpolator object, which defines the time interpolation over the intervalue preceding the keyframe.

The Keyframe class itself is abstract. The type-specific factory methods will return a subclass of Keyframe specific to the type of value being stored. This is done to improve performance when dealing with the most common cases (e.g., float and int values). Other types will fall into a more general Keyframe class that treats its values as Objects. Unless your animation requires dealing with a custom type or a data structure that needs to be animated directly (and evaluated using an implementation of TypeEvaluator), you should stick to using float and int as animations using those types have lower runtime overhead than other types.

Constructor Summary

Keyframe()

Method Summary

abstract Keyframe	clone()
float	getFraction() Gets the time for this keyframe, as a fraction of the overall animation duration.
Interpolator	getInterpolator() Gets the optional interpolator for this Keyframe.
Class	getType() Gets the type of keyframe.
abstract Object	getValue() Gets the value for this Keyframe.
boolean	hasValue() Indicates whether this keyframe has a valid value.
static Keyframe	ofFloat(float fraction) Constructs a Keyframe object with the given time.
static Keyframe	ofFloat(float fraction, float value) Constructs a Keyframe object with the given time and value.
static Keyframe	ofInt(float fraction) Constructs a Keyframe object with the given time.
static Keyframe	ofInt(float fraction, int value) Constructs a Keyframe object with the given time and value.
static Keyframe	ofObject(float fraction) Constructs a Keyframe object with the given time.
static Keyframe	ofObject(float fraction, Object value) Constructs a Keyframe object with the given time and value.
void	setFraction(float fraction) Sets the time for this keyframe, as a fraction of the overall animation duration.
void	setInterpolator(Interpolator interpolator) Sets the optional interpolator for this Keyframe.
abstract void	setValue(Object value) Sets the value for this Keyframe.

Methods inherited from class java.lang.Object

equals, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Constructor Detail

Keyframe

public Keyframe()

Method Detail

ofInt

public static Keyframe ofInt(float fraction,
                             int value)

Constructs a Keyframe object with the given time and value. The time defines the time, as a proportion of an overall animation's duration, at which the value will hold true for the animation. The value for the animation between keyframes will be calculated as an interpolation between the values at those keyframes.

Parameters:

fraction - The time, expressed as a value between 0 and 1, representing the fraction of time elapsed of the overall animation duration.

value - The value that the object will animate to as the animation time approaches the time in this keyframe, and the the value animated from as the time passes the time in this keyframe.

ofInt

public static Keyframe ofInt(float fraction)

Constructs a Keyframe object with the given time. The value at this time will be derived from the target object when the animation first starts (note that this implies that keyframes with no initial value must be used as part of an ObjectAnimator). The time defines the time, as a proportion of an overall animation's duration, at which the value will hold true for the animation. The value for the animation between keyframes will be calculated as an interpolation between the values at those keyframes.

Parameters:

fraction - The time, expressed as a value between 0 and 1, representing the fraction of time elapsed of the overall animation duration.

ofFloat

public static Keyframe ofFloat(float fraction,
                               float value)

Constructs a Keyframe object with the given time and value. The time defines the time, as a proportion of an overall animation's duration, at which the value will hold true for the animation. The value for the animation between keyframes will be calculated as an interpolation between the values at those keyframes.

Parameters:

fraction - The time, expressed as a value between 0 and 1, representing the fraction of time elapsed of the overall animation duration.

value - The value that the object will animate to as the animation time approaches the time in this keyframe, and the the value animated from as the time passes the time in this keyframe.

ofFloat

public static Keyframe ofFloat(float fraction)

Constructs a Keyframe object with the given time. The value at this time will be derived from the target object when the animation first starts (note that this implies that keyframes with no initial value must be used as part of an ObjectAnimator). The time defines the time, as a proportion of an overall animation's duration, at which the value will hold true for the animation. The value for the animation between keyframes will be calculated as an interpolation between the values at those keyframes.

Parameters:

fraction - The time, expressed as a value between 0 and 1, representing the fraction of time elapsed of the overall animation duration.

ofObject

public static Keyframe ofObject(float fraction,
                                Object value)

Constructs a Keyframe object with the given time and value. The time defines the time, as a proportion of an overall animation's duration, at which the value will hold true for the animation. The value for the animation between keyframes will be calculated as an interpolation between the values at those keyframes.

Parameters:

fraction - The time, expressed as a value between 0 and 1, representing the fraction of time elapsed of the overall animation duration.

value - The value that the object will animate to as the animation time approaches the time in this keyframe, and the the value animated from as the time passes the time in this keyframe.

ofObject

public static Keyframe ofObject(float fraction)

Constructs a Keyframe object with the given time. The value at this time will be derived from the target object when the animation first starts (note that this implies that keyframes with no initial value must be used as part of an ObjectAnimator). The time defines the time, as a proportion of an overall animation's duration, at which the value will hold true for the animation. The value for the animation between keyframes will be calculated as an interpolation between the values at those keyframes.

Parameters:

fraction - The time, expressed as a value between 0 and 1, representing the fraction of time elapsed of the overall animation duration.

hasValue

public boolean hasValue()

Indicates whether this keyframe has a valid value. This method is called internally when an ObjectAnimator first starts; keyframes without values are assigned values at that time by deriving the value for the property from the target object.

Returns:

boolean Whether this object has a value assigned.

getValue

public abstract Object getValue()

Gets the value for this Keyframe.

Returns:

The value for this Keyframe.

setValue

public abstract void setValue(Object value)

Sets the value for this Keyframe.

Parameters:

value - value for this Keyframe.

getFraction

public float getFraction()

Gets the time for this keyframe, as a fraction of the overall animation duration.

Returns:

The time associated with this keyframe, as a fraction of the overall animation duration. This should be a value between 0 and 1.

setFraction

public void setFraction(float fraction)

Sets the time for this keyframe, as a fraction of the overall animation duration.

Parameters:

fraction - time associated with this keyframe, as a fraction of the overall animation duration. This should be a value between 0 and 1.

getInterpolator

public Interpolator getInterpolator()

Gets the optional interpolator for this Keyframe. A value of null indicates that there is no interpolation, which is the same as linear interpolation.

Returns:

The optional interpolator for this Keyframe.

setInterpolator

public void setInterpolator(Interpolator interpolator)

Sets the optional interpolator for this Keyframe. A value of null indicates that there is no interpolation, which is the same as linear interpolation.

getType

public Class getType()

Gets the type of keyframe. This information is used by ValueAnimator to determine the type of TypeEvaluator to use when calculating values between keyframes. The type is based on the type of Keyframe created.

Returns:

The type of the value stored in the Keyframe.

clone

public abstract Keyframe clone()

Overrides:

clone in class Object